近十年定量核磁共振法应用研究进展

介绍了近十年国内外各类定量核磁共振法在各领域的研究进展。定量核磁共振法(qNMR)作为一种选择性强、准确快捷的定量分析方法,广泛应用于有机化合物的纯度定值。核磁共振法主要分为一维谱(¹H、¹³C、¹⁹F、³¹P-NMR)、二维谱、液相色谱-核磁共振联用法(LC-NMR)、固体NMR等类型。其中,¹H谱是最常用的定量核磁共振方法,广泛应用于各领域;其他一维谱中的分析物信号通常较少或没有杂质干扰,近年也常用于食品、药学等领域。二维谱和LC-NMR联用技术则可以对复杂样品进行定量分析。固体qNMR针对固体样品前处理简便,但相较于液体qNMR研究较少。     

核磁共振定量技术测定原薯蓣皂苷对照品的含量

目的:1H核磁共振定量技术测定原薯蓣皂苷的含量.方法:采用Bruker AVANCEⅡ500MHz超导脉冲傅里叶变换核磁共振波谱仪,以氘代吡啶为溶剂、TMS为内标,测定原薯蓣皂苷的核磁共振氢谱,通过样品定量峰与内标物质响应峰面积及质子当量重量,计算原薯蓣皂苷的含量.结果:以化学位移为δH 5.84处的氢信号作为定量峰,...     

核磁共振定量法测定培美酸甲酯绝对含量

建立核磁共振定量法测定4-[2-(2-氨基-4,7-二氢-4-氧代-1H-吡咯并[2,3-d]嘧啶-5-基)乙基]苯甲酸甲酯(培美酸甲酯)绝对含量。以盐酸吉西他滨为内标,DMSO-d_6和D_2O为溶剂,测定~1HNMR,通过比较样品(A_s)与内标(A_r)的定量峰面积,分别计算3批供试品的含量。样品与内标物质的量比在峰面积比为0.505 3～1.980 0时线性关系良好,线性回归方程为y=0.730 2x+0.032 3(R~2=0.999 9)。精密度、重复性和稳定性试验的相对标准偏差(RSD)分别为0.43%、0.51%、1.12%。平行配制3份样品溶液进样测定,计算3批供试品的百分含量分别为98.37%、97.54%和97.70%,RSD分别为0.12%、0.17%、0.26%,与质量平衡法测定3批结果98.75%、97.16%和97.78%基本一致。经验证,建立的qNMR法简单、快速、准确,可用于培美酸甲酯原料药的含量测定。     

核磁共振波谱内标法测定四氯虫酰胺标样的含量

[目的]采用核磁共振波谱内标法,建立了快速、专属、准确测定四氯虫酰胺标样含量的方法。[方法]使用日本电子公司JNM-ECZ600R超导核磁共振波谱仪,以氘代二甲基亚砜为溶剂,顺丁烯二酸为内标,在测定温度25℃、脉冲宽度8.0μs、延迟时间为5 s、扫描次数8的条件下采集样品氢谱。[结果]以化学位移δ分别为10.55和6.27的四氯虫酰胺和顺丁烯二酸的氢质子峰作为定量峰,其峰面积比y(As/Ar)与质量比x(ms/mr)进行线性回归,相关系数为0.9999。含量测定重复性试验的RSD值为0.38%,稳定性的RSD值为0.77%,测得四氯虫酰胺标样的含量为99.6%。[结论]在没有标准对照品的情况下,核磁共振波谱法可用于四氯虫酰胺的含量测定,该方法具有快速、准确、简便的优点。     

定量核磁共振法测定草铵膦原药的含量

[目的]采用定量核磁共振法建立草铵膦原药的定量方法。[方法]以重水为溶剂、仲丁基脲为内标物,以化学位移分别在d 1.27的草铵膦甲基和d 1.11的仲丁基脲甲基的1H NMR信号作为定量峰。[结果]以草铵膦与仲丁基脲定量峰的峰面积比(As/Ai)对草铵膦与仲丁基脲的质量比(Ws/Wi)进行线性回归,线性相关系数为0.999 9;重复测定同一批次原药含量,变异系数为0.22%。[结论]在无需草铵膦标准品的情况下,该方法可用于测定草铵膦原药的含量。     

定量核磁共振技术的测试流程

随着核磁共振技术的发展,定量核磁共振技术(Quantitative Nuclear Magnetic Resonance,QNMR)广泛应用于制药、食品、生命科学、化工等领域,已成为一种重要的分析方法。结合日常工作,文章综述了QNMR的原理、内标峰和内标物的选择、实验参数设置以及实施方法,为迅速、顺利地开展QNMR实验提供参考。     

核磁共振氢谱法测定注射用微球专用溶剂中硅油的含量

目的：建立测定注射用微球专用溶剂中硅油含量的定量核磁共振氢谱(qHNMR)法。方法：采用Bruker Avance NEO 600型核磁共振波谱仪测定核磁共振氢谱(¹H NMR),脉冲序列zg30,弛豫延迟时间15 s,采样次数16,测定温度25℃,以咖啡因为内标,不加四甲基硅烷(TMS)的氘代氯仿为溶剂,对注射用微球专用溶剂中的硅油进行定量研究,以硅油定量峰与内标定量峰面积之比对其含量(μg)绘制标准曲线,计算注射用微球专用溶剂中硅油含量。结果：硅油含量在6～100μg范围内线性关系良好,r=0.999 9,低、中、高浓度的平均回收率为97.8%(n=9),重复性RSD为9.8%。结论：该方法操作简单快捷、灵敏度高、结果准确,可用于注射用微球专用溶剂中硅油含量的测定。     

核磁共振波谱法测定b型流感嗜血杆菌荚膜多糖中的核糖含量

目的建立核磁共振波谱(nuclear magnetic resonance,NMR)法测定b型流感嗜血杆菌(Haemophilus influenzae type b,Hib)荚膜多糖中核糖含量的方法。方法利用NMR技术中的氢核磁共振波谱(1H-NMR)的定量功能,对不同浓度的D-核糖进行定量分析,验证该方法的精密度及准确度,并与传统化学方法进行比较。结果 NMR法定量结果相对标准偏差(RSD)均小于1.0%,相对误差除最低浓度20 mmol/L为7.4%外,其余浓度均在1%~3%之间,不同浓度的样品回收率在97.2%~107%之间;化学法定量结果 RSD在0.6%~7.9%之间,相对误差在3%~6.5%之间,不同浓度样品回收率在93.5%~105.3%之间;两种方法检测的3批Hib荚膜多糖中核糖含量无明显差别,均在《中国药典》三部(2010版)规定的320~410 mg/g之间。结论 1H-NMR定量方法取样少,可直接定量,该方法精密度高、准确度高、重现性好,且不破坏多糖结构,可应用于细菌荚膜多糖质量控制的核糖定量。     

手性镧系位移试剂核磁共振法测定芳氧丙酸酯类除草剂对映体纯度

1引言手性位移试剂(CSR)在测定对映体纯度上比手性衍生剂法(CDA)和手性溶剂法(CSA)具有更加广泛的应用范围,尤其在测定酯类化合物上。CDA和CSA法都需要先将酯水解为酸或醇,以便与CDA反应,或与CSA形成氢键:而手性位移试剂的优势就在于无需讲进化     

定量核磁共振技术及其在环保型轮胎助剂开发中的应用进展

介绍了欧盟REACH法规对轮胎中多环芳烃(PAHs)含量的限制及所规定的定量核磁共振(QNMR)检测方法对我国合成橡胶工业的影响,综述了QNMR技术的特点、测定PAHs的原理及主要影响参数,提出了QNMR技术在环保轮胎助剂开发中的应用方向。     

Two-dimensional nuclear magnetic resonance of resins

A group of resins was synthesised from a series of phenols and aldehydes, and their structures comprehensively deduced from two-dimensional nuclear magnetic resonance spectroscopy (2-D NMR). Correlation spectroscopy, in particular carbon-proton heteronuclear chemical shift correlation spectroscopy, was shown to be especially incisive in assigning structural features to the NMR signals. The method has permitted fuller structural characterisation of these materials than was heretofore possible, and has identified, inter alia, methylene and methyleneoxy bridges unequivocally: complex substitution patterns in the phenol-derived aromatic rings have also been elucidated. It is demonstrably possible to apply the same techniques to similar complex resin structures, and to utilise these structural insights to determine the mechanistic processes involved in their syntheses.     

核磁共振法测定涤纶长丝含油率

采用核磁共振仪测试涤纶长丝含油率,初步探讨了其在生产过程中的应用。结果表明:与传统洗涤法相比,核磁共振法具有快速、简便、试样不需制备、不称重、不需溶剂的优点,且测试精密度和准确度高。     

Elaidic acid in rat liver identified by gas chromatography and nuclear magnetic resonance spectroscopy

Fatty acid composition has been commonly determined by gas chromatography (GC). In the most commonly used methods, the lipids must be converted into methyl esters or other derivatives of the fatty acids before being analyzed by GC. Nuclear magnetic resonance (NMR) spectroscopy has become one of the most promising methods to determine organic structures, providing useful data for analyzing the fatty acid composition of edible vegetable oils. The major advantage of NMR is that identification of each fatty acid is carried out by evaluation of particular signals. We report in this work the fatty acid profile of rat liver after consumption of diets containing different concentrations of partially hydrogenated vegetable fat. The fatty acid composition was identified by GC, and trans fatty acids were also identified by ¹³C NMR spectroscopy. The results obtained by the ¹³C NMR method were close enough to those obtained by conventional GC.     

Investigations of polymer chains in oriented fluid phases with deuterium nuclear magnetic resonance

Deuterium nuclear magnetic resonance (D n.m.r.) is a potentially powerful technique for exploring molecular structural and dynamical properties of polymer chains in bulk fluids and concentrated solutions. A variety of systems can be investigated (the solid state, elastomeric networks, sheared polymer fluids, chain solutes in liquid crystal solvents, and polymeric liquid crystals), over a wide range of dimensions (local chain properties, rotational isomeric state parameters, behaviour between network junctions or entanglements, evolution of tube distributions, and domain sizes of homogeneous chain alignment). A coarse comparison of low molar mass liquid crystals with condensed phases of entangled polymer fluids and elastomeric networks illustrates the key features of the D n.m.r. technique and establishes a common framework for interpreting experiments.     

Enzyme-catalyzed polymerization of 8-hydroxyquinoline-5-sulfonate by in situ nuclear magnetic resonance spectroscopy

In this report, we describe the use of in situ NMR spectroscopy to elucidate the mechanism of horseradish peroxidase-catalyzed oxidative free-radical coupling of phenols. We demonstrate the potential of the technique for the polymerization of 8-hydroxyquinoline-5-sulfonate (HQS). Based on the structural changes, we establish the involvement of ortho- and para-position protons (to the hydroxyl group) in the oxidative free-radical coupling polymerization with their relative preferences. For example, in HQS, we establish that the positions 2, 4, and 7 are involved in the chemical bonding with the order of preference being 7 ≥ 2 > 4. Analyses of ¹³C-NMR data suggest the formation of C—C- and C—O—C-type coupling bonds during enzymatic polymerization. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1257–1264, 1998     

Isotope-specific analysis of neutron-irradiated lithium aluminate ceramics by nuclear magnetic resonance spectroscopy

The effects of neutron irradiation on lithium aluminate ceramics and the transport and incorporation of tritium into surrounding components are primary concerns in the development of materials for use in tritium production. The high specific activity and volatility of the tritium in activated samples greatly increase the challenges of experimental analysis. This paper reports the determination of structural forms and concentrations of ³H and ⁶Li in irradiated and nonirradiated LiAlO₂ by nuclear magnetic resonance spectroscopy. The experiments find tritium uniformly distributed in hydroxyl groups bridging aluminum centers and lithium in four- and six-coordinated sites. These results demonstrate that measurements can be performed in a nondestructive, safe manner to obtain isotope-selective, quantitative information even on highly hazardous materials.     

Theory of nuclear magnetic relaxation

A theory of nuclear magnetic relaxation centred around the rotation operator is proposed. The theory is applicable in principle to molecules of arbitrary shape, and account is taken of the effects of their inertia. Calculation of relaxation times associated with anisotropic chemical shift and spin-rotational interactions provides illustrations of how the theory may be employed.     

共聚酯中间苯二甲酸含量的NMR测定

介绍了共聚酯中间苯二甲酸含量的测定方法之一———核磁共振法(NMR),表明对于间苯二甲酸含量较低的共聚酯,采用13C谱的测定结果较好。     

C nuclear magnetic resonance spectral analysis of stereosequences in ethylene-propylene copolymer

A number of split peaks dependent on both comonomer sequences and stereosequences were observed in the ¹³C nuclear magnetic resonance (n.m.r.) spectrum of ethylene-propylene (E-P) copolymer. The ¹³C chemical shifts of methylene carbon in stereoisomers of the respective hexad comonomer sequences were predicted by a chemical-shift calculation using the gamma effect on ¹³C chemical shifts and Mark's rotational isomeric state model for E-P copolymer. Assignments of the split peaks that arise from different hexad stereosequences were given by comparison between the observed and calculated chemical shifts. Reference was made to the hexad assignments of comonomer-sequence-dependent peak splittings determined in our previous calculation of ¹³C n.m.r. chemical shifts of stereoregular E-P copolymers. The tacticities were estimated for successive (not separated by ethylene units) propylene units in the hexad sequences.